
SPECIFICATIONS No. 3780 



THE CARE AND OPERATION 

OF 

STORAGE BATTERIES 



AMERICAN TELEPHONE AND TELEGRAPH CO. 
ENGINEERING DEPARTMENT 








Glass / K 
Ronk 4 £ 
CopightK?_ 

COPYRIGHT DEPOSIT. 










A. T. & T. Co.’s 
Specifications No. 3750 

Replacing Bulletin No. 17 '"Storage Batteries” 


THE CARE AND OPERATION 

OF 

STORAGE BATTERIES 


AMERICAN TELEPHONE AND TELEGRAPH CO. 

I) 

ENGINEERING DEPARTMENT 


APRIL, 1915 


9 


5 


(Copyright, 1915, by American Telephone and Telegraph Co.) 


APPROVED: 





American Telephone and Telegraph Co. 

J. J. CARTY, 

Chief Engineer. 



JUN 12 1915 


v<> 
( , *.) 


April, 1915. 


CONTENTS 


Subject Page 

Purpose of Specifications. 1 

General Nature of the Storage Cell. 1 

ELECTROLYTE 

Acid . 2 

Water . 2 

Table of Allowable Impurities in Water. 3 

Care of Electrolyte. 4 

Specific Gravity . 4 

Corrections for Temperature Variations. 5 

Addition of Acid. 5 

Addition of Water. 6 

INITIAL CHARGE 

General . 6 

Installation of Wood Separators. 7 

Charging .:- 7 

Rate and Duration of Charge. 7 

Readings . 8 

Addition of Water. 8 

Specific Gravity . 8 

Voltage . 9 

OPERATION 

Pilot Cell . 9 

General . 9 

Addition of Water. 10 

Displacement Tanks and Blocks. 10 


























Subject Page 

Charging . 10 

General . 10 

Specific Gravity vs. Voltage Method. 11 

Gravity Method . 11 

Voltage Method . 12 

Charging Rate . 12 

Economy of Power. 13 

Regular Charge. 14 

Overcharge . 15 

Voltage at End of Charge. 16 

Voltage and Specific Gravity after Charge. 16 

Floating . 17 

Discharging . 17 

Specific Gravity Variation. 17 

Voltage Limits . 18 

Readings . 19 

General . 19 

Daily Readings . 19 

Weekly Readings . 19 

Exchange Load Readings. 20 

CARE OF THE BATTERY 

Inspection . 20 

General . 20 

Cells in Trouble. 21 

Indications of Trouble. 21 

Treatment . 22 

Special Charging . 22 

Replacing Bolted Connections. 22 





























Subject Page 

Battery in Trouble. 23 

Decrease in Capacity. 23 

Sulphated Plates . 24 

Treatment of Sulphated Plates. 24 

Results of Overcharging. 25 

Treatment of Dry Plates. 25 

Battery or Individual Cells Used but Occasionally. 25 

Battery Temporarily Out of Service. 25 

Putting Battery or Individual Cells Out of Commission 26 
Putting Battery or Individual Cells Into Commission 

Again . 27 

Addition or Renewal of Plates. 28 

Jars and Tanks. 29 

General . 29 

Electrolysis of Tank Linings. 29 

Repairs to Jars or Tanks. 30 

Protective Coating (Paint, etc.). 31 

Sediment . 31 

General . 31 

Removal from Glass Jar Batteries. 31 

Removal from Tank Batteries. 32 

Reburning Plates in Tank Batteries. 33 

Charging Battery after Removal of Sediment. 34 

ACCESSORIES 

Cell Covers . 34 

Hydrometer . 35 

Thermometer . 35 

Automatic Cell Filler. 35 



























GENERAL 


Subject Pa S e 

The Battery Room. 3 d 

Ventilation . 35 

Light . 36 

Protective Coating (Paint, etc.). 36 

Cleanliness . 36 

Records . 37 

General . 37 

Curves of Specific Gravity Readings. 37 

TESTING 

General . 37 

Capacity . 37 

Cadmium Test . 39 

Voltage . 40 

Ampere Hour Efficiency. 40 

Resistance . 40 

SUMMARY OF IMPORTANT POINTS 


SAMPLE REPORT FORMS 
















STORAGE BATTERIES. 


PURPOSE OF These specifications supersede Bul- 
SPECIFICATIONS. letin No. 17 issued January, 1906, on 

the subject ot storage batteries and 
their purpose is to place before the Associated Telephone 
Companies in concise form the latest and most approved 
practice with regard to the operation and maintenance of 
storage cells of the “lead-lead” type which are now in 
general use in telephone central offices. 

GENERAL NATURE The active constituents of a fully 
OF THE STORAGE charged cell of the “lead-lead” type 
CELL. consist of peroxide of lead on the 

positive plates, spongy metallic lead 
on the negative plates, and the electrolyte which is a solu¬ 
tion of sulphuric acid in water. During discharge of the 
cell the action is to convert the active material of both 
sets of plates (or electrodes, as they are frequently called) 
into a form of lead sulphate. During discharge some of the 
acid in the electrolyte combines with the lead of the nega¬ 
tive plates and the lead peroxide of the positive plates to 
form this lead sulphate, which action lowers the specific 
gravity. During charge these actions are reversed; the 
sulphate on the negative plates is reduced to metallic lead, 
the sulphate on the positive plates is oxidized again to 
peroxide of lead, and the specific gravity of the electrolyte 
rises. 

It is to be noted that the sulphate of lead formed during 
the discharge of a cell is entirely distinct in its behavior 
from the hard, dense whitish form which makes its appear¬ 
ance when a cell is carelessly managed and to which refer¬ 
ence is hereinafter made. 


1 


ELECTROLYTE. 


ACID. The electrolyte is dilute sulphuric 

acid and is prepared by diluting a 
suitable grade of sulphuric acid with pure water. Water 
should never be poured into aqid; always pour the acid into 
the water. It is important that the acid used should be 
essentially free from impurities. Some impurities, such as 
platinum, iron, copper, and many other metals, tend to 
cause self-discharge through local action and lower the 
efficiency and capacity of the battery. Other impurities, 
such as hydrochloric, nitric, and other acids, tend to attack 
and to corrode the plates. It is therefore recommended that 
all acid or prepared electrolyte be purchased from the 
manufacturer of the battery or from the Western Electric 
Company. Any material obtained from other sources should 
be carefully tested to determine its suitability for storage 
battery use. 

WATER. It is also essential that the water 

used for preparing the electroyte 
should be pure. Preference should be given to distilled 
water for this purpose, but water taken from any reliable 
source of supply may be used if its suitability for the pur¬ 
pose has been proven by careful testing. 

In case of doubt as to the purity of the electrolyte or its 
ingredients, carefully collected samples should be submitted 
to the manufacturer of the battery for test and advice. 

The samples should be forwarded by express (never by 
mail or parcel post) in clean bottles with glass or rubber 
stoppers, carefully packed to avoid breakage. One (1) pint 
of acid or electrolyte and one (1) quart of water will be 
required for a satisfactory analysis. 

If analysis shows that the amount of impurities contained 
in the water exceeds the amount determined by the manu¬ 
facturer of the batteries as being the maximum ordinarily 
allowable (see table below) distilled water should be used 
unless the manufacturer authorizes the use of the water in 


2 


question on account of favorable operating conditions at 
the particular office concerned. Local conditions will deter¬ 
mine whether it will be more economical to purchase the 
distilled water or to install a water still in the central office. 
In many cases one still could be used to furnish water for 
several neighboring offices. Where distilled water is pur¬ 
chased the source should receive consideration, as it has 
been found that so-called distilled water obtained from local 
steam or ice plants occasionally contains more of the harm¬ 
ful impurities than average city water. 


TABLE OF ALLOWABLE IMPURITIES IN WATER. 


Max. Ordinarily Normal for 
Permitted Raw Water 

Substance Parts Grains per Parts per Remarks 



per 100,000 

Gal. 

Chlorine 

1.0 

0.3 

Nitrates 

1.0 

Trace 

Iron 

0.15 

0.03 


Organic & 10. (approx.) 6. 

volatile 

Fixed 10. (approx.)6. 
residue upon 
evaporation 


100,000 


0.1 to 1.0 (high) 

Worst impurity; 
attacks plates, 
forming up the 
positives. 

Trace not 
noticeable 

Attacks positives 
but is then de¬ 
composed. 

0.005 to 0.1 
(high) 

Attacks and sul¬ 
phates the posi¬ 
tives. 

1 to 3 

(sometimes 10) 

Danger of form¬ 
ing harmful or¬ 
ganic acids. 

Variable 

These salts tend 
to neutralize the 
acid and in some 
cases affect the 

negatives. 


An excess of any one of these substances, except iron, 
is usually cause for rejection of the water. The figure for 
iron, while not up to the harmful limit, is abnormally high 


3 






for most waters, and therefore, cause for suspicion, and 
indicates some source of contamination, such as rusty pipes, 
which at times might render the water dangerous. 

CARE OF It is also necessary to take ex- 

ELECTROLYTE. treme care that no impurities enter 

the electrolyte after it has been 
added to the cell. Trouble is most likely to occur from the 
introduction of metallic substances into a cell, such as tools, 
bits of wire, etc. Should it be known that any metallic sub¬ 
stance has fallen into a cell, it should be immediately re¬ 
moved. If the substance is not immediately removed, or if 
there is any doubt as to whether the electrolyte has been con¬ 
taminated the solution should immediately be changed. Be¬ 
fore putting in the new electrolyte the cell should be thor¬ 
oughly flushed with water. The change should be made 
when the battery is discharged and just before charging. Do 
not allow the plates to dry. (See page 25). 

In this connection it should be remembered that should 
there be iron work above the cells injurious iron salts may 
be formed by the action of the acid fumes or by ordinary 
rusting unless the iron is properly protected by a reliable 
paint or varnish (see page 31), and that these salts may fall 
into the cells. 

SPECIFIC The electrolyte furnished for use 

GRAVITY. in storage cells should have a specific 

gravity of 1.210: a leeway of five 
points (.005 Sp. Gr.) above or below this value is permissible. 
It is prepared by mixing one (1) part by volume of acid 
(of 1.835 specific gravity—66° Beaume) with four (4) parts 
by volume of water. The acid must be poured into the 
water; never pour water into the acid. The acid should 
be poured into the water slowly and carefully, not only to 
prevent excessive heating, but more particularly splashing, 
on account of the painful and dangerous character of acid 
burns. The specific gravity of the solution should be 
determined only when it has completely cooled. The speci- 


4 


fic gravity of the solution should be finally adjusted by the 
addition of small amounts of acid or of water until the 
prescribed specific gravity has been secured. The vessel 
used for mixing must be a lead-lined tank, one of glazed 
earthenware, or one of wood which has not been used for 
any other purpose, such as a new wash-tub. Wooden ves¬ 
sels, however, must not be used for storing electrolyte. 

Corrections for Temperature Variations. Allowance 
must be made for variations in the temperature of the 
electrolyte from the normal value of 70° F., in order that 
all specific gravity readings may be upon the same basis 
for purposes of comparison. 

To correct a given hydrometer reading for variations 
from the normal temperature of 70° F., for each three (3) 
degrees of temperature variation, one point, (.001 Sp. Gr.), 
should be subtracted if the temperature is below 70° F. or 
should be added if the temperature is above 70° F. For 
example, a hydrometer reading of 1.212 with the temper¬ 
ature at 64° F. would be 1.210 corrected, while a reading 
of 1.212 at 76° F. would be 1.214 corrected. 

Wherever specific gravity is referred to in these speci¬ 
fications corrected values are meant unless otherwise stated. 


ADDITION OF On account of loss of acid from 
ACID. the electrolyte through absorption by 

the sediment and through spraying 
at the end of charge there is a gradual lowering of the 
specific gravity of the electrolyte, the rapidity of the change 
depending on the work the battery does and the care with 
which it is operated. When on account of the above causes 
the specific gravity of the electrolyte at the end of an over¬ 
charge and at normal temperature has fallen to 1.180 it 
should be brought up to standard by the addition of new 
electrolyte of 1.210 specific gravity instead of water when 
replacing evaporation loss. Under special conditions where 
properly qualified supervision is available, acid of 1.400 
specific gravity may be used to bring up the gravity of the 


5 




electrolyte. Improper use of 1.400 gravity acid may injure 
the plates. Adjustment of the specific gravity should not 
be necessary oftener than about once every two (2) or 
three (3) years. 

NEVER UNDER ANY CIRCUMSTANCES RAISE 
THE SPECIFIC GRAVITY OF THE ELECTROLYTE 
IN A CELL WITHOUT FIRST DETERMINING IF 
THE LOW GRAVITY IS DUE TO PARTIAL CHARGE, 
SHORT CIRCUITS, OR GRAVITY READINGS UN- 
CORRECTED FOR TEMPERATURE. 

ADDITION OF Only pure water (see page 2) 

WATER. should be used to replace loss by 

evaporation. The electrolyte must 
never be allowed to get below the top of the plates nor 
must the cells be filled too full. The water should be added 
at the top of the cell with sufficient frequency to keep the 
electrolyte from 1/2 inch to 3/4 inch above the top of the 
plates. The water should be added carefully and splashing 
or slopping avoided. It is recommended that the water be 
added immediately before or after starting a charge, pref¬ 
erably an overcharge, after the cell readings have been 
taken. The ensuing charge will then cause the water to 
become thoroughly mixed with the electrolyte. 


INITIAL CHARGE. 

GENERAL. New battery plates, as received 

from the manufacturer, are general¬ 
ly in a more or less sulphated condition, particularly the nega¬ 
tive plates. When these plates are installed in the cells 
and covered with electrolyte, the amount of sulphate on all 
the plates is increased to some extent due to absorption of 
acid from the electrolyte. The purpose of the initial charge 
is to completely convert this sulphated active material of 
the positive and negative plates into lead peroxide and 


6 


spongy lead respectively, thereby preparing the battery for 
service. 

Before the electrolyte is put into the cells, the circuits 
connecting the battery with the charging source must be 
complete and of the proper polarity. The positive pole of 
the charging source must be connected with the positive 
end of the battery. The positive plates are of a brownish 
color, the negatives of a light gray. Sometimes new nega¬ 
tive plates will have whitish spots. These are harmless 
and will generally disappear after the cells have been in 
service a few months. The grids of new positive plates are 
frequently covered with a thin scale. This is also harmless 
and will flake off in time. Charging in the reverse or wrong 
direction will seriously injure the battery. 

As the life of the battery is materially influenced by the 
initial charge, it is of great importance that this charge be 
complete before allowing the battery to discharge. 

Installation of Wood Separators. Cells are usually fitted 
with wood separators and these should be installed in ac¬ 
cordance with the directions furnished by the manufacturer. 
Wood separators are shipped wet and must not be allowed 
to become dry. If there is any delay in setting up the bat¬ 
tery the separators should be left in the packing cases and 
kept wet by being frequently sprinkled with water, at least 
once a week, the lid of the case being removed while 
sprinkling. 

CHARGING. Rate and Duration of Charge. Ti e 

charge should be started as soon as 
practicable after the electrolyte is in all the cells, but under 
no circumstances should there be a delay of more than four 
(4) days in starting the charge. The charge should, if 
possible, be at the normal rate recommended by the manu¬ 
facturer, and should be continued until both the specific 
gravity and voltage of each cell reach a ten-hour maximum, 
i. e. show no further rise or increase during a period of ten 
(10) hours and bubbles of gas are being freely given off 
from all the plates, both positives and negatives. The posi- 


7 








tive plates will gas some time before the negative plates 
begin to gas. If it is necessary to charge at a rate less than 
normal the 10-hour period must be proportionately in¬ 
creased. The temperature of the electrolyte should be 
watched, and if it reaches 110° F., the charging rate must 
be reduced or the charge temporarily stopped until the tem¬ 
perature lowers. 

The minimum time required, at normal rate, for the ini¬ 
tial charge is generally from thirty (30) to fifty (50) hours, 
the shorter time applying to types of cells in which the 
negative plates are shipped in a partially formed condition. 
If the charging rate is less than normal the time required 
for the charge will be correspondingly increased. If neces¬ 
sary, the charge can be interrupted, for instance over night, 
but the interruption should not be longer than ten (10) or 
twelve (12) hours. In case the charge is interrupted, par¬ 
ticularly during its earlier stages, or if it is not started soon 
after the electrolyte is in the cells, the total charge required 
(in ampere hours) will be greater than if the charge is con¬ 
tinuous and started at once. The charging current should 
not be allowed to exceed the normal rate by more than 
ten (10) per cent, and after the first twenty-five (25) hours 
of the charge must be kept as near the normal rate as 
possible. 

Readings. As a guide in following the progress of the 
charge, readings should be taken and recorded hourly, as 
indicated by the accompanying “Storage Battery Initial 
Charge Report” form. The gassing should also be watched, 
and if any cells are not gassing or are not gassing as much 
as the surrounding cells they should be carefully examined 
(see page 21) and the cause of the trouble removed. 

Addition of Water. Water should be added to the cells 
as required to keep the electrolyte at its normal level, from 
1/2 inch to 3/4 inch above the top of the plates. 

Specific Gravity. The specific gravity will fall rapidly 
after the electrolyte is added to the cells owing to the for- 


8 



mation of lead sulphate on the plates as explained on page 
6, and the water from the wood separators, and will sub¬ 
sequently rise gradually as the charge progresses, until it 
again reaches its original value or thereabouts. 

If the specific gravity of any cell at the completion of 
the initial charge, with the level of the electrolyte at the 
proper height above the plates, is more than five points 
(.005 Sp. Gr.) above or below the mean value recommended 
by the manufacturer, it should be adjusted to the proper 
figure. Due allowance should, of course, be made for 
temperature, and electrolyte should be added if the gravity 
is low while some of the electrolyte should be replaced by 
water if the gravity is high, keeping the surface as nearly 
as possible 3/4 inch above the top of the plates. 

Voltage. The voltage at the end of charge, while ap¬ 
proximately 2.55 volts per cell, is not a fixed value, and for 
this reason a definite voltage should not be aimed for. 


OPERATION. 

EXCESSIVE CHARGING MUST BE AVOIDED, AND 
A BATTERY MUST NOT BE UNDERCHARGED, 
OVERDISCHARGED, OR ALLOWED TO STAND 
COMPLETELY DISCHARGED. 

PILOT CELL. General. One of the cells of the „ 

battery is to be used as a guide in 
the operation of the battery as a whole. For this purpose 
a readily accessible and well lighted cell is to be selected 
and known as the “pilot cell. ,, Where all the plates in the 
battery are not of the same age, as when the plate equip¬ 
ment is increased or partial renewals made, the pilot cell 
should be one of those having the oldest plates. Readings 
are to be taken on this cell with sufficient frequency to in¬ 
dicate its state of charge and discharge, which will thus 
serve as a guide in the operation of the battery as a whole. 


9 










The pilot cell, when once selected, should not be changed, 
unless the cell has to undergo special treatment or repairs. 

Addition of Water. The height of the electrolyte in the 
pilot cell should be kept at a fixed point, and above the top 
of the plates. This may be done automatically, or a small 
quantity of w T ater may be added by hand often enough (at 
least once a day) to keep the height accurately at the proper 
point. This will prevent the sudden drop in the specific 
gravity of the electrolyte consequent upon the addition of 
a considerable quantity of water and the following increase 
in specific gravity as it evaporates. If not filled automati¬ 
cally, the fixed point should be marked in a convenient man¬ 
ner; for instance, in a glass-jar battery by a narrow painted 
line on the outside of the jar, or in tanks by an S-shaped 
strip of lead hung over the edge of one of the glass support¬ 
ing plates. 

Displacement Tanks and Blocks. In order to obtain as 
great a range in gravity on charge and discharge as possible, 
it is necessary in batteries in which the number of plates 
per cell is less by four (41 or more than the full tank capa¬ 
city that the excess of electrolyte in the pilot cell should be 
displaced. A tank specially constructed for this purpose 
and filled with 1.210 electrolyte is used in batteries set up 
in tanks; if in glass jars, a wooden block, properly treated 
and weighted, may be used. 

CHARGING. General. It is important that the 

battery should be given the proper 
amount of charge, as indicated below, but excessive charging 
must be avoided, as not only will an unnecessarily rapid 
accumulation of sediment and excessive evaporation of the 
electrolyte result, but, what is more important, the life of 
the plates will be very much shortened. 

From the standpoint of power economy, life of the battery 
and provision for emergency reserve, the best practice is 
the method which embraces what may be called a “regular 
charge,” to be given when the battery is from one-third 


10 








(1/3) to one-half (1/2) discharged, and an “overcharge,” to 
be given weekly if it is necessary to charge the battery daily 
(either six or seven days a week), or once every two weeks 
if the regular charge is not given so often. 

Specific Gravity vs. Voltage Method. The readings of 
the specific gravity of the electrolyte in a pilot cell, or of 
the voltage of the battery can be used as a guide in follow¬ 
ing the charge. The specific gravity method is to be pre¬ 
ferred, owing to its being independent of the rate of charge, 
and more accurate than the voltage method. The latter 
method is not recommended except under very special con¬ 
ditions. Voltage readings are to be used as a check on the 
gravity and also in cases where due to the character (2- 
plate cells) or inaccessibility of the cells, the gravity method 
is not practicable. 

Gravity Method. It has been previously stated (see page 
1) that during discharge the specific gravity of the electro¬ 
lyte is lowered, owing to the removal of part of its sulphuric 
acid to form lead sulphate, and that, on charging, this lead 
sulphate is decomposed. The sulphuric acid thus set free 
again enters the electrolyte, which as a result is raised to a 
higher specific gravity. The quantity of sulphuric acid 
which is removed from the electrolyte is dependent on the 
quantity of active material which is transformed, or practi¬ 
cally on the number of plates in the cell and the extent to 
which they are discharged. The change in the specific grav¬ 
ity of the electrolyte depends on the relation of the quantity 
of acid uniting with active material to the quantity of elec¬ 
trolyte in the cell. If the quantity of electrolyte is increased, 
the plates remaining the same, the fall in gravity due to a 
given discharge (in ampere hours) will be lessened as the 
same quantity of acid is taken from a larger quantity of 
solution. In using the gravity method for observing charge 
and discharge, it is therefore essential that the ratio of the 
volume of the electrolyte to the quantity of active material 
should always remain constant. This is the reason for the 
rules for the care of the pilot cell which provide for keeping 







the level of the electrolyte at a fixed point and supplying a 
displacement tank when four or more plates less than the 
full tank capacity are installed. 

Voltage Method. When, owing to the character (2-plate 
cells) or inaccessibility of the cells, the gravity method of 
operation cannot be used it is necessary to operate the bat¬ 
tery by the voltage method. When using this method it 
is important that the charging rate should be kept uniform, 
and it is preferable that the charging should be at the nor¬ 
mal rate, as under these conditions the best specific rules 
for voltage operation can be given. If the charging rate is 
less than normal, it is necessary to make a reduction in the 
required voltage for end of charge, which can be only ap¬ 
proximately estimated. In all cases where the voltage 
method of operation is used it is essential that for at least 
two (2) hours preceding the completion of the charge the 
charging rate should be uniform and not less than fifty (50) 
per cent, of the normal rate, as satisfactory voltage opera¬ 
tion cannot be secured except under well-defined conditions. 
As mentioned above, the voltage method should be used only 
when the gravity method is not practicable. 

Charging Rate. The normal charging rate is usually the 
eight-hour discharge rate, i. e., a rate which will give a com¬ 
plete discharge of the battery in eight (8) hours. To bring 
a battery from a state of complete discharge to a state of 
complete charge will, due to the battery losses, require 
charging at the normal rate for a longer period than eight 
(8) hours. 

The normal rate is assigned by the manufacturer as a 
desirable rate at which to charge the battery. Any charging 
rate which does not cause gassing is, however, permissible, 
even several times the normal rate, during the early part of 
a charge following an extended discharge. To avoid ex¬ 
cessive wear of the plates a high rate must not be used 
toward the end of charge and the normal rate must not be 
exceeded after the battery starts to gas. If the battery 
voltage is not allowed to exceed an average of 2.30 volts 


12 


per cell at any time, when charging at rates higher than 
normal, gassing will be avoided. With the gravity method 
of operation it is not necessary to charge at a uniform rate, 
as the gravity indicates closely the state of charge. The 
gravity method of operation is recommended wherever it is 
possible. 

Economy of Power. The charging generator attains its 
greatest efficiency in transforming power into electrical 
energy for telephone purposes when it is supplying a current 
at from 3/4 to full load. At certain periods of the day the 
office load is comparatively heavy, and if during these peri¬ 
ods the generator is operated at or near its rated output 
some economy in the cost of power can be effected. This 
is due, first, to the fact that the generator is thereby work¬ 
ing at a high efficiency and, secondly, to the fact that energy 
for the operation of the office is supplied directly from the 
generator, and the losses occurring when energy is trans¬ 
formed in the battery are avoided. 

In planning for the economical operation of the power 
plant it is necessary to consider the rated output of the 
generator, the exchange load, and the proper charging rate 
for the battery. As the relation of the rated output of the 
generator to the other factors may vary considerably in 
different installations, the following rules are given for 
guidance in securing economical operation: 

1. When the rated output of the generator is sufficient 
to carry the office load and the normal rate of the battery, 
charge the battery at the normal rate. 

Note: Where the generator size permits, and it is 
desired to shorten the time of charge, the normal rate 
may be exceeded as previously outlined, until the battery 
reaches the gassing stage. 

2. When the rated output of the generator is less than 
the office load plus the normal rate of the battery, charge 
at full load on the generator. 


13 



Note: Where a reserve generator is provided and is 
arranged for parallel operation, it may be found desir¬ 
able to run both machines during the period of heaviest 
office load. 

3. In applying the above rules it should be noted that it 
is economical to carry as much of the office load from the 
generator as can be done efficiently. This may make it 
advisable in some cases, particularly under rule 1, to reduce 
the generator output in order to prolong the time of charge. 
It is ordinarily not economical to operate the smaller charg¬ 
ing sets (less than approximately 300 amperes capacity) at 
less than half load, or the larger sets at less than one quar¬ 
ter load. 

Regular Charge. The allowable drop in the specific grav¬ 
ity of the electrolyte before starting the charge depends in 
any particular case upon the reserve capacity desired, and 
the charging, whether done daily or less frequently, should 
be started at such a time as will insure that this capacity is 
available at the time the attendant regularly leaves the of¬ 
fice for the day. 

The twenty-four hour central office drain on a battery 
having one day’s capacity will cause the specific gravity of 
the electrolyte in the pilot cell to fall approximately the 
number of points shown in the table on page 18, and in the 
case of a battery having three days’ capacity the drop in 
specific gravity during twenty-four hours will equal approxi¬ 
mately one-third of these values. 

If the voltage method only is used for observing charge 
and discharge, as for small 2-plate cells, no single rule can 
be given for determining when the charge should be started, 
as the voltage varies with the rate of discharge. For spe¬ 
cial directions on the voltage method see under “Voltage 
Limits” page 18. 

The battery should be charged until: 

(a) The gravity of the pilot cell has risen to a value 
which is five points (.005 sp. gr.) below the maximum 
reached on the preceding overcharge; for instance, if the 


14 


maximum reached on the preceding overcharge was 1.209, 
the gravity to be reached on the regular charge is 1.204. 

(b) The voltage across the battery has risen to a 
value which is .05 to .10 volts per cell below what it was 
on the preceding overcharge, the charging rate being the 
same in both cases; for instance, if the maximum voltage 
per cell attained on the overcharge is 2.52, the voltage 
per cell to be reached on the regular charge is from 2.42 
to 2.47 volts per cell (see ‘Voltage at End of Charge,” 

page 16). 

(c) The cells are all gassing decidedly but not as 
freely as on overcharge. 

Overcharge. If the battery is charged daily (six or seven 
days per week), then once each week, on the same day of 
every week, the regular charge should be prolonged until: 

(a) The gravity of the pilot cell has reached a one- 
hour maximum, i. e., five (5) successive 15-minute read¬ 
ings of this cell show no further rise. If the charging 
rate is less than normal the length of the overcharge 
period should be proportionately increased. For instance, 
if the charging rate is half the normal, the number of 
successive 15-minute readings should be increased to nine 
(9). 

(b) The voltage across the battery has reached a 
maximum, five (5) successive 15-minute readings show¬ 
ing no further rise, the charging rate being kept constant. 
At charging rates less than normal the number of suc¬ 
cessive 15-minute readings should be increased as under 
(a). 

(c) The cells are all gassing freely. 

If the battery is not charged daily (less than six days per 
week) then the overcharge should be given only once every 
two (2) weeks. 

When giving the cells the “overcharge,” arrangements 
should be made to give the latter portion of the charge at a 
uniform and, where practicable, at approximately the normal 
rate, whether specific gravity or voltage operation is fol¬ 
lowed. As the determination of the end of the overcharge 


15 


depends on the securing of a series of successive uniform 
gravity and voltage readings, it is important that, during 
the last hours of the overcharge, the charging rate should be 
approximately constant. 

Voltage at End of Charge. The voltage at the end of 
charge is not fixed throughout the life of a battery, but will 
vary, due to several causes, namely, the age of the battery, 
the temperature and specific gravity of the electrolyte, and 
the charging rate. Therefore, a maximum voltage as de¬ 
scribed under “Overcharge” above, and not a definite or 
specific voltage must be considered when using the voltage 
method in determining the end of charge. 

When first installed, the voltage at the end of over¬ 
charge, with the normal charging current flowing, should be 
approximately 2.55 volts per cell, with the temperature at 
70° F., (under exceptional conditions the voltage per cell 
may reach 2.70), but as the age of the battery increases this 
voltage will gradually decrease, until in some cases, with 
both the charging rate and temperature normal, it will have 
fallen to 2.40 volts per cell, or thereabouts. 

The effect of changes in temperature on the final charg¬ 
ing voltage is that it is noticeably lowered with an increase 
in the temperature above normal (70° F.) and correspond¬ 
ingly increased with lowered temperatures, irrespective of 
the age of the battery. 

Higher or lower rates of charging than the normal will, 
respectively, produce slightly higher or lower final charging 
voltages. 

Voltage and Specified Gravity after Charge. After the 

completion of a charge and the cutting off of the current, 
the voltage per cell will fall quite rapidly to between 2.05 
and 2.10 volts. 

As the discharge is started the voltage will fall to ap¬ 
proximately 2.00 volts per cell, depending on the rate. 

Also, after the completion of a charge, particularly an 
overcharge, the specific gravity of the electrolyte will rise 
slightly, due to the passing off of the gas bubbles formed 


16 


during the charge, for this reason the pilot cell gravity read¬ 
ings must be taken before the charging current is cut off. 

FLOATING. When the battery has been given its 

proper charge, it may often happen 
that the office load will remain for some time at a value 
which is a considerable proportion of the generator rating. 
If the cost of power is low, it may be profitable to run the 
generator to carry the office load and thus avoid the trans¬ 
formation losses in the battery. This can be done if the 
battery is “floated ,” i.e., if the output of the generator is 
regulated approximately equal to or slightly less than the 
office drain. Temporary fluctuations in the office drain will 
result in slight discharge of the battery if they are in excess 
of the average, or in slight charge if they are below the 
average. 

DISCHARGING. Specific Gravity Variation. The fall 

in gravity of the electrolyte is very 
closely in direct proportion to the ampere hours taken out 
and for this reason is the best indication of the amount of 
discharge. 

The total gravity drop for a complete discharge varies 
for different types and sizes of cells depending on the relative 
bulk of the plates and electrolyte. As the small size cells of 
any type have a relatively large bulk of electrolyte they 
therefore have a smaller range than the large size cells 
of the same type. The following table gives the approximate 
range for a complete discharge for cells of different types 
equipped with the full number of plates. If the cells have 
less than the full number of plates, the range in gravity is 
proportionately reduced, except in the case of the pilot cell, 
which should be equipped with a device for displacing the 
excess electrolyte (see “Displacement Tanks and Blocks” 
page 10). For telephone service in general, however, charg¬ 
ing should be started when the specific gravity on discharge 
has fallen approximately from one-third (1/3) to one-half 
(1/2) the range given in the table (see “Regular Charge” 


17 


page 14). In emergency cases, however, all the capacity 
that the battery will give and still maintain service may be 
used without regard to the specific gravity drop. 


SPECIFIC GRAVITY RANGE FOR COMPLETE 

DISCHARGE 


TYPE 

E 

F-STYLE 

A JARS 


F- 

LEAD 

LINED TANKS 

No. of 
Plates 

5 

7 

9 

11 

13 

15 

9 

11 

13 

15 

9 

11 

13-15 

17-19 

21-23 

25-27 

Sp. Gr. 
Range 

(Approx.) 

22 

30 

33 

37 

40 

42 

32 

36 

40 

42 

22 

24 

26 

29 

31 

32 


TYPE 


No. of 
Plates 

9 

11 

13 

15 

17 

19 

21-23 

25-27 

29-33 

35-39 

41-49 

51-59 

61-75 

Sp. Gr. 
Range 

(Approx.) 

26 

29 

31 

33 

35 

37 

30 

40 

42 

43 

44 

45 

46 


Voltage Limits. The voltage of a battery is affected by 
the rate of charging or discharging and for this reason can¬ 
not be used to indicate the state of the charge or discharge 
without taking the rate into consideration. The following 
table gives the average cell voltage at different discharging 
rates to which it is considered safe to allow a cell to drop 
and yet insure a reserve in case of emergency: 


Discharging Rate 
Normal 
3/4 “ 

1/2 “ 

1/4 “ 

1/10 “ 


Voltage per Cell 
1.90 
1.92 
1.94 

1.96 

1.97 


For allowable voltage limits when making a capacity 
test see page 38. 


18 





































As stated above, the fall in gravity method of deter¬ 
mining the amount of discharge is the most reliable and is 
to be preferred under ordinary conditions. 

READINGS. General. As a guide in following 

the operation and general condition 
of the battery, and also for a record of the same, it is im¬ 
portant that readings be regularly taken and recorded. The 
following are suggested: 

Daily Readings. The specific gravity and temperature 
of the pilot cell, the voltage across the battery and the 
battery current should be read and recorded just before 
the beginning and end of every charge. Readings of the 
pilot cell specific gravity should also be taken hourly dur¬ 
ing the charge but need not be recorded. 

On days when the battery is not charged the gravity 
and temperature of the pilot cell should be read and re¬ 
corded at the usual time of starting the charge. 

It is desirable, when there is a regular attendant stationed 
in the office, to take a reading of the specific gravity of 
each cell at least once each day. These readings need not 
be corrected for temperature and need not be recorded. If 
the gravity readings indicate anything unusual in connec¬ 
tion with the battery, individual cell voltage readings should 
also be taken. 

Weekly Readings. Before starting the overcharge, if the 
battery is overcharged weekly, and also on the correspond¬ 
ing day of the off week if not overcharged weekly, a gravity 
reading of each cell in the battery should be taken and 
recorded. The above cell readings should be carefully ex¬ 
amined and any cell showing a falling off in specific gravity 
relative to the surrounding cells should be noted, and as 
soon as possible inspected and the cause removed. (See 
“Inspection,” page 20). During the overcharge, and beginning 
when the specific gravity reaches a value from two (2) to 
five (5) points below the maximum reached on the preced¬ 
ing overcharge, readings of the pilot cell specific gravity, 


19 


and the battery voltage and current, should be taken and 
recorded at 15-minute intervals, until five (5) successive 
readings of the specific gravity and voltage show no further 
rise. Within 15 minutes after stopping the overcharge a 
gravity reading of each cell should be taken and recorded. 

Exchange Load Readings. It is suggested that at inter¬ 
vals of about six (6) months, readings of the exchange load 
be taken over a period of twenty-four (24) hours. These 
readings should be taken at 15-minute intervals during the 
day and, when practicable, at hourly intervals during the 
night. Care should be taken to select a day representative 
of the average conditions of service (preferably a peg-count 
day), rather than one when extraordinary conditions pre¬ 
vail, as on holidays and Sundays. These readings will assist 
in checking up the operation of the battery. 


CARE OF THE BATTERY. 

INSPECTION. General. A careful inspection of 

each cell should be regularly made. 

The most suitable time for an inspection is before the 
overcharge, so that if any trouble is discovered it can be 
removed in time for the cell to get the benefit of the 
overcharge. 

In making the inspection an ordinary incandescent light 
on an extension cord can be used and a careful examination 
should be made between the hanging lugs to see that the 
separator dowels are in place and the lugs are not touching; 
also anything unusual in the color or appearance of the 
plates should be carefully noted. 

Some moss (spongy lead) may form on the top of the 
negative plates, and should it accumulate to a considerable 
amount it should be removed before it bridges across to 
the positive plates and causes a short circuit. A heavy ac¬ 
cumulation of moss usually indicates excessive charging. 

On the top of the positive plates a thin coating of fine 
powder will form which can be easily brushed off. With 


20 


proper charging this powder will be of a dark yellowish color 
and the surface of the grid beneath a dark chocolate color; 
with excessive charging the powder will also be of a dark 
chocolate color. 

Special attention should be given to cells that read low 
at the time the cell readings are taken. Look for the cause 
of the trouble and remove it as soon as possible, and not 
later than the beginning of the overcharge. Short-circuits 
should be removed with a thin strip of glass, hard rubber 
or well-seasoned wood; never use metal. 

Near the end of the overcharge all cells should be ex¬ 
amined to see that they are gassing freely. The height of 
the electrolyte affects the appearance of gassing; if the 

electrolyte is down to the top of the plates and the cell 

otherwise normal, the amount of gas given off will apparently 
be much less than when the electrolyte properly covers 
the plates. 

All cell connections should be inspected to see that they 
are clean and tight. 

In addition to the above, the accumulation of sediment 
in the bottom of the cells should from time to time be noted; 
it must not be allowed to reach the plates (see “Sediment,” 
page 31). 

CELLS IN Indications of Trouble. The follow- 

TROUBLE. ing are the chief indications of 

trouble in a cell: 

FALLING OFF IN SPECIFIC GRAVITY OR VOLT¬ 
AGE relative to the surrounding cells. 

LACK OR DEFICIENCY OF GASSING on overcharge 
as compared with surrounding cells. 

COLOR OF POSITIVE PLATES markedly lighter 
than those in surrounding cells. 

In case any of the above symptoms are found in a cell, 
examine carefully for the cause and REMOVE IT AT 
ONCE. 


21 


Treatment. The above symptoms in a cell indicate that 
it is “low” i.e., has fallen below the rest in its state of 
charge. If the cause is discovered and removed immediately, 
it will usually be restored to normal condition by the fol¬ 
lowing overcharge. If then only partially restored, it must 
be carefully watched during the ensuing week. If the next 
overcharge does not completely restore it, or if the original 
deficiency was excessive, it may be necessary to give it a 
special charge. 

Special Charging. The first and simpler method of treat¬ 
ing a low cell is to overcharge the battery, but care should 
be taken not to carry this to excess. 

The second method is by giving an individual charge 
while the battery is on discharge. This charge can usually 
be given over special leads from the generator side of the 
regular charging switch. Care should be taken not to close 
this switch while giving the individual charge. In the case 
of large generators having multiple plate field rheostats, it 
may be necessary to disconnect one or more of the plates 
in order to sufficiently reduce the generator voltage. 

Before putting a cell that has been in trouble into service 
again, care should be taken that the cell has been fully 
charged, this being determined by continuing the charge at 
normal rate until at least a five-hour gravity and voltage 
maximum is reached, six (6) or more successive hourly 
readings of each showing no further rise and gas is being 
freely given off from all the plates. If the charging rate is 
less than normal the length of time at maximum must be 
proportionately increased. 

Replacing Bolted Connections. When bolted connections 
have been disconnected they should be replaced with care 
to avoid heating and increase in resistance of the battery 
circuit. The following method is recommended: Wipe the 
bolts and straps clean, scraping the abutting surfaces of the 
straps to a bright finish, then join in the usual manner 
after dipping the brass bolt in vaseline. When the con- 


22 


nections have been tightened, scrape a small V-shaped groove 
approximately 1/16 inch to 1/8 inch deep across the top of 
the lugs where they meet by means of a sharp file or other 
square-edged tool. Rub a piece of tallow in the groove 
and melt the two surfaces together with a very hot solder¬ 
ing iron. Several hours after bolting the connections they 
should be gone over and tightened and after the succeeding 
charge is completed they should be tightened a third time. 
This is necessary to take up the “slack” due to the deforma¬ 
tion of the lead under pressure. 

BATTERY IN Decrease in Capacity. In some 
TROUBLE. cases a battery as a whole, although 

receiving its usual amount of charg¬ 
ing, may show a decrease in capacity before this can be 
accounted for by the natural wear on the plates. If after 
prolonging three (3) or four (4) of the usual overcharges 
to nine (9) 15-minute maximum readings (two-hour maxi¬ 
mum), and with normal routine restored, the capacity again 
shows a decrease, it is probable that the fault is with the 
negative plates, in which case a reduction of the specific 
gravity of the electrolyte will generally restore them to 
normal condition. 

The most suitable value to which to reduce the gravity 
is approximately 1.170 at end of overcharge. This reduction 
is accomplished by drawing off some of the electrolyte and 
replacing with water. After reducing, charge to a ten- 
hour gravity maximum; if the specific gravity rises during 
the charge to a value greater than 1.170 again reduce to 
this value. In such cases it is preferable to continue operat¬ 
ing the battery at this low gravity for the remaining life 
of the plates. If, however, it is desired to restore the 
gravity to its normal value in order that the operating routine 
may be the same at all offices, this should be done gradually 
by replacing evaporation with 1.210 electrolyte until the 
normal value is reached. In any case, however, the battery 
should be operated with the low gravity electrolyte for at 
least two months. 


23 


Sulphated Plates. During the discharge of a battery there 
is being formed sulphate of lead, as explained under “General 
Nature Of The Storage Cell” on page 1. If, however, charg¬ 
ing is neglected, the sulphate reaches a condition which 
tends to fill the pores of the plates and make the active 
material dense and hard. It is this condition which is 
ordinarily referred to as “sulphated.” 

The cause of this condition is some form of abuse, such 
as: standing discharged for some length of time; habitual 
undercharging; neglecting evidence of trouble in individual 
cells; adding acid to the cell to restore the specific gravity 
instead of bringing the acid out of the plates by proper 
charging. 

The lead sulphate formed in a normal discharge of a 
battery is in a form in which it absorbs the charge very 
readily. When a battery is “sulphated,” as ordinarily ex¬ 
pressed, the sulphate is then in an abnormal condition and 
absorbs the charge with difficulty, and the ordinary charge 
is insufficient. 

Sometimes new negative plates have whitish spots. This 
is not sulphate, but hydrate. It is not dangerous and will 
generally disappear after the cells have been in service 
a few months. 

Treatment of Sulphated Plates. The reduction of ab¬ 
normal sulphate can be accomplished by prolonged charging, 
preferably at about one-half the normal rate, the charge 
being continued until at least a ten-hour gravity and voltage 
maximum is reached, eleven (11) or more successive hourly 
readings of each showing no further rise and gas is being 
freely given off from all the plates. 

In extreme cases of sulphating, when a battery has been 
taken out of service improperly by withdrawing the electro¬ 
lyte while the cells are in a discharged condition and then 
allowing the plates to dry without thoroughly washing them, 
the reduction of the sulphate can best be accomplished by 
prolonged charging as above but in extremely weak electro¬ 
lyte, about 1.050 specific gravity. (See “Putting Battery Or 
Individual Cells Into Commission” page 27). 


24 


Results of Overcharging. Should a battery be repeatedly 
overcharged to excess an abnormal amount of active material 
will be formed on the positive plates which may cause them 
to buckle. Part of this excess material will be thrown off 
causing a rapid accumulation of sediment and the formation 
of moss on the top of the negative plates. 


TREATMENT OF If for any reason the negative 

DRY PLATES. plates of a cell have been allowed 

to dry, a long time will be required 
for charging, the time usually being 
from thirty (30) to fifty (50) hours at the normal rate, or 
its equivalent in ampere hours at a lower rate. For this 
reason, drying of the negative plates in a working battery 
is to be avoided. 

Positive plates, if dry, will require but a comparatively 
short charge; if they are in a fully charged state when taken 
out of a cell, from six (6) to eight (8) hours will be suffi¬ 
cient; if discharged, then somewhat longer, depending on 
the extent of discharge and length of time they have been 
exposed to the air. 

In any case both the positive and negative plates of a 
cell must be fully charged before being allowed to discharge 
(see “Special Charging,” page 22). 


BATTERY OR 
INDIVIDUAL 
CELLS USED BUT 
OCCASIONALLY. 

out of circuit. 


If the battery is used but occasion¬ 
ally or is standing idle, it should be 
given a freshening charge every 
two (2) weeks; this also applies to 
any cells that may be temporarily 


BATTERY Under exceptional circumstances it 

TEMPORARILY may be necessary temporarily to 

OUT OF SERVICE, take the entire battery out of service 

for repairs. In such a case the best 
procedure is to substitute a portable battery as the charging 
generator alone should not be used for current supply on 


25 


account of the noise developed by these machines and the 
unreliability of the arrangement. In substituting the port¬ 
able battery for the central office battery care should be 
taken not to interrupt the current supply to the office. 

If a portable battery is not available, the noise of the 
machine may be sufficiently reduced by bridging several 
water rheostats in multiple across the charging mains. When 
water rheostats are used they should be connected across 
the mains with the charging generator in operation. At first 
the plates of the rheostats should be kept far apart, but, 
as the electrolyte is removed from the cells to allow the 
repairs to be made, the plates should be moved nearer to¬ 
gether, until when the circuit through the battery is broken 
the current flowing through the rheostats is the same as 
that originally flowing through the battery. When the bat¬ 
tery is restored to service, the plates of the rheostats should 
gradually be separated until the proper current through the 
battery is again obtained. This method should not be used 
except as a last resort after all efforts to obtain a portable 
battery have failed. An automobile battery can often be 
used to advantage. 

PUTTING BATTERY If the use of the battery or any of 
OR INDIVIDUAL its cells is to be discontinued for a 
CELLS OUT OF period not exceeding twelve (12) 

COMMISSION. months and it will not be conven¬ 
ient to give it a freshening charge 
at regular intervals (see ‘‘Battery Used But Occasionally”) 
care should be taken that an overcharge is given just before 
the idle period. Water should be added to the cells during 
the overcharge so that the gassing will insure thorough 
mixing. The level of the electrolyte should be about 1/4 
inch from the tops of the jars or tanks. After the over¬ 
charge is completed, remove the fuses to prevent the use 
of the battery during the idle period. Although not likely, 
the level of the electrolyte may, due to excessive evapo¬ 
ration during the idle period, fall below the tops of the plates. 
If this should occur, add water to keep them covered; if in 


26 


a place where freezing is apt to occur, stir the electrolyte 
after adding the water, as thoroughly mixed electrolyte 
will not freeze solid. 

If the battery is to be entirely out of service for over 
twelve (12) months, then proceed as follows: After thor¬ 
oughly charging and determining that there are no low 
cells, syphon off the electrolyte which may be used again 
if desired. As each cell becomes empty immediately fill it 
with fresh, pure water. When water is in all the cells, 
allow them to stand twelve (12) or fifteen (15) hours; then 
draw off the water and immediately remove the wood sep¬ 
arators. The cells will then be in condition to stand in¬ 
definitely. If the old electrolyte is to be saved it should be 
stored in carboys thoroughly cleaned and tightly sealed 
to keep out impurities. The old separators should be thrown 
away and new ones used when the battery is again put in 
service. 

If there is any considerable amount of sediment in the 
cells, advantage should be taken of the out-of-service period 
to clean them thoroughly before the sediment dries and 
becomes hard. 

PUTTING BATTERY If the electrolyte has not been with- 
OR INDIVIDUAL drawn, all that is required is to add 
CELLS INTO COM- water, if needed, to the cells and 
MISSION AGAIN, give an overcharge until the spe¬ 
cific gravity of the electrolyte has 
ceased rising over a period of five (5) hours. 

If the battery has been standing without electrolyte, 
proceed as follows: Equip cells with new separators and 
immediately fill them with either new electrolyte of the 
proper specific gravity (usually about 1.210) or, if the old 
electrolyte has been saved, add enough new to replace that 
lost in handling. When all the cells are filled the charge 
should be started. 

This charge is similar to the initial charge of a new 
battery. The rate should be normal, and continue for a 
period of ten (10) hours after the specific gravity and the 


27 


voltage of each cell have ceased rising. From thirty (30) 
to fifty (50) hours at the normal rate will be the minimum 
time required to complete this charge as explained under 
“Initial Charge.” If the rate is less than normal, the time 
required will be correspondingly increased. It is of the 
utmost importance that this charge be complete. 

ADDITION OR In adding new plates to batteries, 

RENEWAL OF either as partial renewals or to 

PLATES. obtain greater capacity, the follow¬ 

ing method is recommended: 

1. In cases where the batteries have been installed six 
(6) months or less, or one (1) year if the battery has been 
charged less frequently than once every other day and the 
plates of which are consequently but slightly worn, the addi¬ 
tion can be made by simply installing the new plates in the 
same cells with the old plates. The new negative plates 
in such cases must be furnished in a charged condition and 
must be so ordered in the requisition. Charged negatives 
are shipped wet and must be kept so until installed; if they 
are allowed to dry they will require a charge of from thirty 
(30) to fifty (50) hours as explained under “Initial Charge” 
page 6. 

Plates of like kind but of different age should not be 
installed in the same cells except under the above conditions. 

2. When the addition is made to a battery which has 
been installed longer than given in (1) the plates should 
be grouped so that like plates are of the same age, but old 
negatives and new positives, or vice versa, may be installed 
in the same cells. 

3. Old plates that may remain after setting up the 
battery and are in good condition should be thoroughly 
washed, dried and returned to stock to be used for making 
additions to batteries of like age. 

4. In case (2) the cells should be arranged in sequence 
as given below, beginning at either end of the battery: 

(a) Cells containing all old plates. 


28 


(b) Cells containing all old negatives and all new 

positives. 

(c) Cells containing all new negatives and all old 

positives. 

(d) Cells containing all new plates. 

In this case charged negatives are preferable but not 
essential. 

New positives and charged negatives which have not 
been allowed to dry require a relatively short initial charge 
(about 10 hours), which may be given to the battery as a 
whole, but to assume a predetermined amount of charge is 
dangerous and the charge must not be considered complete 
until the specific gravity and voltage, with the current at 
or near normal, have reached a two-hour maximum. 

If dry negatives are used the long charge required for a 
new battery will be necessary (see “Initial Charge” page 
6). If such negatives are installed in only part of the 
cells, such cells should preferably be separately charged 
(see “Special Charging” page 22). 

JARS AND TANKS. General. Care should be taken to 

prevent the lead flaps on lead lined 
wood tanks from becoming bent in so that they touch the 
wood-work, in order that the electrolyte, if any collects on 
the flaps, may fall clear of the tanks. Tanks as received 
from the manufacturer have wood packing strips under the 
lead flaps to protect them from being bent out of shape. 
These should be removed before putting the battery into 
service. 

Electrolysis of Tank Linings. Care must also be taken 
to prevent the tank flaps of adjacent cells from coming in 
contact as this will cause electrolysis of the tank linings. 
The linings may also be damaged if the elements come in 
contact with them. 

Tanks must be kept dry and clean in order to prevent 
leakage to ground, as a very small leakage of current from 
the cells to ground may in time corrode the tank linings by 


29 


electrolytic action. With tank batteries mounted on other 
than oil insulators particular care must be taken to keep 
the insulators free from dirt and acid-laden moisture (see 
“Cleanliness” page 36). Oil insulators require only in¬ 
frequent cleaning. 

Repairs to Jars or Tanks. If for any reason a jar or a 
tank has to be removed, the plates should be taken out, and 
the negatives immediately placed in a non-metallic vessel, 
(one of lead excepted), containing clean water, or in the 
free space of adjacent cells; the positives may be allowed 
to dry. The wood separators should first be removed and 
stored in the free space of adjacent cells; this should be 
carefully done to avoid breakage. Broken or damaged sep¬ 
arators should be discarded and new ones provided in their 
place. Care should be taken that neither the negative plates 
nor the wood separators be allowed to dry out (see “Treat¬ 
ment Of Dry Plates,” page 25). 

While the cell is out of circuit, the remaining cells 
should be charged at a rate which will maintain the bus 
voltage at or above the minimum required to operate the 
office. 

Upon completion of repairs, the plates and wood sep¬ 
arators should be replaced and immediately covered with 
electrolyte. The cell should not be connected into circuit 
during discharge of the battery, but preferably just before 
starting a charge, in order that the plates may receive the 
benefit of the ensuing charge. If the cell readings indicate 
that it is then not fully charged it should be given special 
treatment (see “Cells In Trouble” page 21). If, on account 
of a broken jar, the plates have become dry, the cell will 
require a prolonged charge (see “Treatment Of Dry Plates” 
page 25). 

In order to avoid delay in case a glass jar becomes 
broken it is recommended that a spare jar be always kept 
on hand at the central office. 


30 


PROTECTIVE To properlv preserve the battery 

COATING (Paint, woodwork, particularly the boxes 
etc.). of lead-lined tanks, and also the 

metal work, care must be taken to 
keep these parts well protected. 

The woodwork being thoroughly painted at the start, 
oiling it occasionally with boiled linseed oil, applied with a 
cloth rather than a brush, is recommended; repainting will 
then be necessary less frequently. A satisfactory paint is 
one with a heavy asphaltum base. 

For metal work which is not lead or lead coated the 
above paint may also be used. Exposed copper connections 
may be further protected by coating with vaseline. If cor¬ 
rosion starts, thoroughly clean and repaint at once. In 
cleansing remove the corroded material by scraping and then 
washing with bicarbonate of soda solution. Do not at any 
time allow either the products of corrosion or the washing 
solution to fall into the cells. 

SEDIMENT. General. The accumulation of sedi¬ 
ment in the bottom of the cells must 
be watched and removed when the clearance under the 
plates has been reduced to 1/2 inch. However, due to the 
circulation of the electrolyte when the cell gasses on charge 
the sediment is usually deepest under the middle plates, and 
if it is levelled over the bottom of the cell its removal can 
be deferred for some time. The levelling can be done by 
using an L-shaped device made of wood or of metal not 
appreciably acted upon by the electrolyte, such as aluminum; 
a heavy copper w'ire protected by rubber tubing can be 
used. Under no circumstances must the sediment be allowed 
to reach the plates as, if this occurs they will deteriorate 
rapidly due to the short circuit thus formed. . 

Removal from Glass Jar Batteries. To remove the sedi¬ 
ment from glass jar batteries having bolted connections be¬ 
tween the cells, the best method, except possibly in the 
case of the largest size cells of considerable weight, is, 


31 


after first fully charging the battery, to lift the elements out 
of the jars in rotation at the same time closing the battery 
circuit with a jumper. In handling the elements the sep¬ 
arators should be disturbed as little as possible; if any are 
damaged they should be replaced with new ones. Pour off 
the clear electrolyte into a spare clean jar or carboy; dump 
the sediment and wash the jar with water; replace elements 
in jar and pour in the electrolyte, adding enough new of 
1.210 specific gravity to cover the plates. The gravity should 
be adjusted to normal as outlined under “Addition Of Acid” 
page 5. For instructions regarding the replacement of 
bolted connections see page 22. The elements must not be 
exposed to the air except for the very shortest possible 
time, and must not be allowed to dry out (see “Treatment 
Of Dry Plates” page 25); for this reason only one cell at a 
time should be emptied, cleaned and refilled. While one 
cell is being cleaned the remaining cells should be charged 
at a rate which will maintain the bus voltage at or above 
the minimum required to operate the office. 

A modification of the above method, where a spare bat¬ 
tery and sufficient storage capacity for the electrolyte from 
a number of cells are available is to first take down several 
cells, pouring the electrolyte into a container, and use all 
new electrolyte of 1.210 specific gravity for these cells. The 
removed electrolyte is then to be adjusted to 1.210 specific 
gravity by adding 1.400 specific gravity acid; this is then 
used for the second lot of cells taken down and so on 
through the rest of the battery. This method insures the 
automatic adjustment of gravity as the work progresses 
and the proper gravity is secured with minimum labor. 

Removal from Tank Batteries. If the cell connections 
are burned together as in tank batteries, the sediment can 
be taken out by using a special form of scoop for drawing 
it from beneath the plates and then removing it from the 
jar or tank. The scoop used should be made of hard wood 
(preferably boiled in paraffine) or of aluminum and may be 
obtained from the manufacturer. In cells having a large 
number of plates the scoop will not reach the sediment in 


32 


the middle of the cell and it is therefore necessary to take 
out several of the middle plates in order to remove this 
sediment. A thin board the width of the plates should be 
inserted in the open space thus made and used as a backing 
against which to hold the sediment in the scoop. After the 
sediment is removed the specific gravity of the electrolyte 
must be adjusted to normal (see “Addition Of Acid” page 5). 

Reburning Plates in Tank Batteries. In cases where the 

removal of sediment by the scoop method necessitates cut¬ 
ting out a few plates from the cells the lugs should be cut 
in a V-shape so that when they are replaced they can be 
burned from the bottom of the cut and the V filled up. The 
plates can be readily reburned into place by means of a 
hydrogen flame or by a hot carbon rod, some of the cells 
of the battery being used as a source of current for heating 
the carbon. The latter method will usually be the more 
convenient where only a few plates are to be burned. If a 
large number of plates are to be burned the hydrogen flame 
is recommended. 

The arc burning outfit consists of a carbon holder with 
cable, clamps and 1/4 inch carbon rods. A burning tong or 
mould is placed on the lug to prevent any molten lead from 
escaping. 

From three (3) to six (6) cells are required for this 
work and the number chosen in any case should be suffi¬ 
cient to heat the carbon to a bright cherry red while it is 
in contact with the joint. A little experience will soon en¬ 
able one to determine when a satisfactory degree of heat is 
obtained. 

The cable is connected by means of the clamp to a cell 
in the battery the required number of cells away from the 
joint to be burned, and either positive or negative to it. 
Care should be taken that good contact is made by the 
clamp, the lead being scraped thoroughly clean before the 
connection is made. The carbon should be sharpened to a 
long point like a lead pencil and should project not more 
than three (3) inches from the holder. The latter should 
be cooled off occasionally by plunging it, carbon and all, 


33 


into a pail of water. After being used for a short time it 
will be found that the carbon will not heat properly, due 
to a film of scale formed on the surface. This should be 
cleaned off with a knife or file, as occasion requires. 

Additional lead to make a flush joint should not be 
added until the metal of the pieces to be joined has melted. 
1 he carbon should be moved around to insure a solid joint 
at all points. 

Blue or smoked glasses must be worn during the burning 
operation. 

Charging Battery after Removal of Sediment. After the 

sediment has been removed from all the cells the battery 
should be given an overcharge, continuing until a five-hour 
gravity maximum is reached. At the end of the charge the 
specific gravity of the electrolyte should again be adjusted, 
if necessary, to normal. 

ACCESSORIES. 

CELL COVERS. To reduce the diffusion of acid 

spray, the amount of evaporation, 
and the danger of foreign matter falling into the electrolyte, 
a glass cover should be laid across the top of each cell. 
Covers for two-plate type cells are moulded with lips to 
prevent them from being accidentally displaced. For larger 
cells the covers are made of sheet glass and leave sufficient 
room to permit the addition of water and the taking of 
hydrometer and thermometer readings without removing 
the cover. In certain cases of glass jar batteries, creeping 
of the electrolyte along the glass covers to the outside of 
the jars may occur. This is usually due to the cells not 
being level and can be overcome by allowing one edge of 
the cover to rest inside the jar on the top of the plates. 
Covers should be kept clean by occasionally removing them 
from the cells and washing. 


34 


HYDROMETER. The hydrometer used should prefer¬ 
ably be of the plain type and of the 
proper size for the cells in which it is to be used, (see 
table below). Signalling hydrometers may be useful in 
some cases but are not recommended for general use. 


Hydrometer 

Type 

B 

E 

H 


Used with 
Cells, Type 

BT, CT, B, C 
PT, ET, D, E 
F and larger 


THERMOMETER. A mercury thermometer designed 

to float in the electrolyte should be 
used. The calibration scale recommended is marked with 
degrees Fahrenheit on one side and with temperature- 
gravity corrections on the other. 

AUTOMATIC CELL An automatic cell filler on the pilot 
FILLER. cell which will keep the electrolyte 

in this cell at the proper height is 
recommended for use with all batteries of type E cells 
and larger. 


GENERAL. 

THE BATTERY Ventilation. The battery room or 
ROOM. casing must be properly ventilated 

by means of one or more suitable 
vents, in order that the gasses given off from the battery 
during charge may be promptly removed, the air kept dry 
and the temperature moderate. Do not bring an exposed 
flame into the battery room or casing while the battery is 
being charged or before the room or casing has been en¬ 
tirely freed of gas. It is always desirable to have one or 
more windows in the battery room. 

If the room temperature is very high—that is, consid¬ 
erably over 80° F.—for any great length of time, the life 


35 


of the plates may be somewhat shortened. If the temper¬ 
ature is low, no injury to the battery will result, but the 
available capacity is reduced during the period of low 
temperature. 

It is important that the circulation of air should be 
sufficient to keep the racks, insulators, and cells free from 
dampness which might cause grounding of the battery itself 
or its connecting circuits. 

Light. The provision for illumination should be such 
that all parts of the battery can be readily inspected at any 
time, day or night. An outlet (protected against attack by 
acid fumes) should be provided to which a lamp on an ex¬ 
tension cord can be connected. 

Protective Coating (Paint, etc.). The walls and ceiling 
of the battery room should be painted with a white lead 
or combination white lead and zinc white paint, preferably 
tinted a light yellow or cream color, as these colors readily 
diffuse the light and are not very susceptible to acid stains. 
If the door or window casings are of metal particular care 
should be taken to keep them well protected. 

The floor of the battery room or casing should be painted 
with a black asphaltum paint slightly thinned with turpen¬ 
tine to accelerate the drying. At least four coats are usually 
required. 

Cleanliness. Cleanliness in the battery room is essential. 
The floor should be washed frequently and the tanks, trays, 
racks, insulators and all metal work should be frequently 
wiped off. If there is any metal work over the battery this 
should be given particular attention. At longer intervals 
(at least once a year) the floor should be washed with a 
saturated solution of bicarbonate of soda (ordinary cooking 
soda) and all the apparatus in the room should be wiped 
off with a cloth moistened with the same solution in order 
to neutralize any accumulation of acid spray from the elec¬ 
trolyte. Acid is present as long as the soda effervesces. 
Rinsing with water should follow the application of the 


36 


soda solution and the room should be thoroughly ventilated 
to insure complete drying. The soda solution should not be 
allowed to get into the cells. 

RECORDS. General. For conveniently recording 

the daily and weekly readings, the 
accompanying Storage Battery Weekly Report” form is 
suggested. 

Curves of Specific Gravity Readings. It is also suggested 
that curves be plotted showing the specific gravity of each 
cell at the end of each overcharge. These curves will indi¬ 
cate changes in the condition of each cell over a consider¬ 
able length of time and will show at a glance whether or not 
the battery has been receiving proper attention. The at¬ 
tached form, “Overcharge Specific Gravity Readings On 
Individual Cells” is suggested for this purpose. 

X 

TESTING. 

GENERAL. At such intervals as may be thought 

necessary to determine whether the 
cells meet the requirements of the Specifications under which 
they are furnished the following tests may be made. 

CAPACITY. The test for capacity should be 

made after the battery has received 
an overcharge and it has been determined that every cell is 
tully charged. 

The capacity test at the 8-hour rate may conveniently 
be made in service by using a water rheostat to supplement 
the switchboard and battery machine loads. Instead of 
using a water rheostat, the charging generator can be used 
as a motor to supplement the switchboard load as follows: 
After disconnecting one terminal of the shunt reversing 
coil of the circuit breaker and connecting the charging set 
to the battery in the usual manner, the generator rheostat 
may be adjusted to permit the battery to drive the gen¬ 
erator, care being taken not to exceed the rated current 


37 


output of the generator. When the current taken by the 
generator is more than enough for the combined no-load 
losses, power will be delivered by the motor to the line. 
Where sufficient motor generator capacity is not available 
a gas engine generator set may be used, the engine fur¬ 
nishing a brake, adjustable within certain limits if necessary, 
by varying the compression at the relief valve. 

With the usual arrangement where the power board am¬ 
meter is provided with a zero center scale and a shunt in 
the common charge and discharge lead, the total battery 
discharge current can be read direct. Where no common 
shunt is available the generator ammeter leads should be 
reversed. 

This test should be made under the direction of an 
engineer and care should be taken not to seriously over¬ 
speed a gas engine set, or a motor generator set in the 
event that the motor should be accidentally disconnected 
from the line. 

The capacity test should be timed so that complete 
discharge will be reached shortly after midnight, or at 
some other time when the office load is light. The battery 
should be immediately charged so that the office will not be 
without battery reserve longer than is necessary. 

It is not generally practicable in telephone service to 
discharge the battery sufficiently to obtain its full capacity, 
i.e., until the battery voltage reaches an average of 1.75 volts 
per cell. On this account the test should be considered 
complete when, while discharging at the 8-hour rate, the 
voltage of any individual cell falls to 1.75 volts, provided 
this does not bring the total battery voltage below an aver¬ 
age of 1.82 volts per cell, which is the minimum required to 
operate the office. The capacity obtained by stopping the 
test at this voltage limit is approximately 94 per cent. (93% 
to 95%) of the full capacity of the battery. Under normal 
operating conditions the average discharge rate is appre¬ 
ciably less than the 8-hour rate and the capacity obtainable 
from the battery under these conditions is somewhat greater 
than is obtainable at the 8-hour rate. 


38 


The readings recommended for the test, beginning when 
the discharge is started, are as follows: Current, battery 
voltage, pilot cell voltage, specific gravity and temperature 
at least ionce each half hour; individual cell voltage, specific 
gravity and temperature at least once each hour. A complete 
set of readings should also be taken at completion of the 
discharge. All voltage readings must be taken with current 
flowing, but the final gravity and temperature readings may 
be taken immediately after the discharge is stopped. The 
temperature of the battery room should be recorded at the 
beginning and end of the test. 

After the battery voltage has fallen to an average of 
about 1.90 volts per cell, individual cell voltage readings 
should be taken at frequent intervals (not exceeding 15 
minutes apart) in order to locate any cells which may be 
appreciably below the average at the end of the discharge. 

The test for full rated capacity may be made any time 
between 1^2 and 2]/ 2 years after installation for batteries 
receiving one (1) overcharge a week, or any time between 
two (2) and three (3) years for batteries receiving one (1) 
overcharge every two (2) weeks. 

CADMIUM TEST. The cadmium test is a refinement in 

storage battery testing that is apt 
to be misleading unless handled by experienced men, and 
therefore, its general use is not recommended. When 
properly carried out, however, the cadmium test is of value, 
in cases where low capacity is experienced, in determining 
whether the positive or negative plates are the cause. 

In using the cadmium to determine the condition of the 
plates, local conditions, such as temperature, rate of dis¬ 
charge, etc., have to be taken into consideration as well as 
the results given by the cadmium, and not until considerable 
experience has been had in using the cadmium should much 
dependence be placed on the readings. 

In any case, if it is thought desirable to make use of the 
cadmium test, complete instructions for doing so should be 
obtained from the manufacturer of the batteries. 


39 


VOLTAGE. The overcharge voltage should be 

measured while the normal charging 
current is flowing, after the voltage and gravity have ceased 
to rise. 

The discharge voltage should be measured during a 
capacity test, as outlined above. 

AMPERE HOUR The ampere hour efficiency test may 

EFFICIENCY. conveniently be made when the 

capacity test is carried out. Just 
before stopping the overcharge which immediately precedes 
the capacity test discharge the specific gravity of the pilot 
cell should be very accurately read. The capacity test dis¬ 
charge should then be made, and on the following charge 
the number of ampere hours required at normal rate to 
raise the pilot cell gravity to the value attained on the 
preceding charge should be noted, allowance being made 
for any difference in cell temperature on the two charges. 
The ratio of the ampere hours obtained on the discharge to 
the ampere hours required on the charge will be the ampere 
hour efficiency of the battery. 

RESISTANCE. On account of the relatively small 

electrical inductance and capacity of 
the conventional lead plate sulphuric acid type battery, the 
internal impedance can generally be determined with suffi¬ 
cient accuracy by measuring the “virtual internal resistance.” 
This may be done by noting the instantaneous change in 
battery terminal voltage for sudden changes in charge and 
discharge currents, the value for resistance being the quotient 
obtained by dividing the voltage change by the current 
change. Rapid changes and readings are necessary to min¬ 
imize the effects of polarization, which would not be present 
with measurements made by alternating current. The 
average value obtained from several sets of readings should 
be taken. 

Unless it is suspected that a battery is abnormal, re¬ 
sistance tests ordinarily need not be made. 


40 


SUMMARY OF IMPORTANT POINTS. 

1. Give the battery the proper amount of charge but 

avoid excessive charging. See page 9 

2. Give a “regular charge” daily or every other day and 
an “overcharge” weekly or every two weeks as required. 

See page 10 

3. Start “regular charge” when sp. gr. of pilot cell has 
fallen the proper number of points below the value at¬ 
tained at end of preceding overcharge. See page 14 

4. Stop “regular charge” when sp. gr. of pilot cell reaches 

a value 5 points below the value attained at end of 
preceding overcharge. See page 14 

5. When giving an “overcharge,” continue charging until 
the sp. gr. and voltage show no change in 5 successive 
readings taken at 15-minute intervals. (Proportionately 
longer if charging rate is less than normal). 

See page 15 

6. Whenever possible use the specific gravity method for 

following the state of charge. See page 11 

7. Correct all hydrometer readings to 70° F. See page 5 

8. Battery and cell readings must be regularly taken and 
recorded on the forms provided for this purpose. 

See page 19 

9. Unless the pilot cell is equipped with an automatic 

cell filler add water to this cell at least once a day to 
keep electrolyte at the fixed level. See page 10 

10. Use only pure water for replacing evaporation. 

See page 6 

11. Do not allow top of plates in any cell to become ex¬ 
posed. See page 6 

12. Contamination of the electrolyte by foreign matter must 

be avoided. See page 4 

13. Inspect each cell at regular intervals. See page 20 

14. Keep battery room well ventilated at all times. 

See page 35 

15. Do not bring an exposed flame into the battery room. 

See page 35 


41 


















A. T. & T. Co. Form E-118 
Replacing Form 1158 


STORAGE BATTERY INITIAL CHARGE REPORT. 

. ...-.- Company. 

-. Exchange. Battery No - - Cells. Type. .. 


SHEET No_ 

Equipment . Plates per Cell. 

Capacity . Plates per Cell. 


Charge Started . ~p. M - 


-/9/-. Completed ..pM. 


191 


PIL.OT CELL. [CELL NO... 


INDIVIDUAL. CELL READINGS. 


Date 

Time 

amperes 

Ampere 

Hours. 

NO. OF 
CELLS 1* 

Circuit 

Total volts 

FOR CELLS 

in Circuit. 

Average 

VOLTS PER 

Cell in 
Circuit. 

Htorom. 
Reading 
[Observed 
Sp. Gr.J 

Temper¬ 

ature 

ELECTRO¬ 

LYTE 

Specific 
Gravity 
(COR'ECT'O 
TO 70° F. 

VOLTS 

TEMP. Air. 

Evert 

6 HRS. 

Date 

ANO 

Time 




Cell 

Htorom. 

Reading 
not Cor'o. 

VOLTS 

HTOROM. 

REAOING 

VOLTS 

HTOROM. 
REAOING 
NOT COR'D. 

VOLTS 













I 



















2 



















3 



















4 



















5 



















6 



















7 



















8 



















9 



















10 



















II 



















12 



4 
















13 



















14 



















15 

















\' 


16 

















A 


17 




1 












-4— 



18 




H 















19 














yJ 


$ 



20 




- 1 










X 

_^ 

_ 



21 




J 










- 

—A.— 




22 




- 









- 







Average Height 

. -INCH. 

of Electrolyte 

.INCH. | 

Above Plates - 

.INCH. 



















S 


* - 




DIRECTIONS. 

The readings called for on the left side of the sheet are to be 
taken hourly front the start to the end of the charge, carefully 
noting any interruption or change in the charging rate. 

. . Charge at the normal rate until the voltage and specific grav¬ 
ity show no rise for at least 10 hours, the readings being taken 
once an hour; the. maximum voltage will probably be reached ear¬ 
lier than the maximum specific gTavity, so that particular care must 
be taken that both voltage and specific gravity have reached the 
required maximum before the charge is stopped. 

The first set of individual cell readings is to be taken 10 
hours before the minimum time required for the charge, the second 
set at the minimum time, and the third set [if necessary! just be¬ 
fore the end of charge. Minimum time required norma) rate 

for initial charge for Type 3T, CT. PT, ET, B and C cells is 30 
hours; for Type D. E, F and G cells. 50 hours, At rates less than 
normal, the length of the charge will be proportionally increased. 

A temperature of 110° F must hot be exceeded. 

The normal height pf electrolyte above plates is % inch and 
water should occasionally be added to maintain thi* level. 

REMARKS 

[These to cover anything unusual in connection with the installs- 
tion and the initial charge, and to be made as complete as possible 1 



















V 

_ i 













hr* 











rp 























c 





















































































































































































































































Readings taken by 

Readings approved by 


























DUPLICATES OF THIS REPORT TO DE FORWARDED BY THE WESTERN ELECTRIC COMPANY 
TO THE LOCAL OFFICE OF THE BATTERY COMPANY. 





















































































































































































































































A. T. A T. CO. FORM C-127 


STORAGE BATTERY WEEKLY REPORT 


. . .COMPANY. 

BATTERY NO. ... —.CELLS TYPE. 

WATER WAS ADDED TO REPLACE EVAPORATION.. 

CELLS NOT GASSING PROPERLY ON OVERCHARGE. NOS 


EXCHANGE 


DATE. FROM 


EQUIPMENT.PLATES PER CELL 


TO. ,...191 _(INCL.) 

CAPACITY--..PLATES PER CELL 


(DATE) 


IS PILOT CELL EQUIPPED WITH AUTOMATIC FILLER 


CELLS GIVEN SPECIAL ATTENTION DURING WEEK (STATE ATTENTION GIVEN UNDER • REMARKS ') Nos. 


DAILY READINGS 


REMARKS 



before charge 

START 

end of charge 



PILOT CELL (CELL NO--) 

BATTERY 

BATTERY 

PILOT 

:ell 


BAT 

TERY 

DAY 

TIME 

HYDROM. 

READING 

OBSERVED 
SP. GR.) 

TEMPER¬ 

ATURE 

ELECTRO¬ 

LYTE 

SPECIFIC 
GRAVITY 
(.CORRECT 
ED TO 
70° F.) 

VOLTS 

AMPERES 

CHARGING 

AMPERES 

TIME 

HYDROM. 

READING 

OBSERVED 
SP. GR.) 

TEMPER¬ 

ATURE 

ELECTRO¬ 

LYTE 

SPECIFIC 

GRAVITY 
CORRECT¬ 
ED TO 

70°- F.) 

VOLTS 

AMPERES 




































































































(THESE TO COVER ANYTHINS UNUSUAL IN CONNECTION 
WITH THE OPERATION OF THE BATTERY.) 



directions 

DAILY READINGS. 

“Refor^^harge"'readings'?o °be ^takerf^just mVtT&c is started. 

» g 4Sto be ^ space for the -End of Charge- reading, for that day, hut record the specific, gravity 

be taWen. Th* voltage readings are on the battery as a whole, not on 

individual, ceils. 

below the maximum reached on the preceding overcharge. 






































































































































































































































































A.T.AT.CO. roi)M K- 128 

OVERCHARGE SPECIFIC GRAVITY READINGS ON INDIVIDUAL CELLS 


....Company--Exchange 

Battery No.--Celts. Type- Equipment-Plates per Cell. Capacity..Plates per Cell. 
















































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































